This invention relates to a control arm and spring arrangement for a suspension assembly, and more particularly, the invention relates to a control arm and spring arrangement that permits a change in caster and camber during wheel travel.
There are numerous types of suspension configurations commonly used in modern vehicles. One type of suspension configuration includes an upper and lower control arm supporting a knuckle there between. The control arms are typically rigid members stamped from steel or cast from another metal. A spring and shock absorber is typically connected to a portion of the lower control arm and a frame portion to provide a particular spring rate and control the movement of the wheel supported on the knuckle. The geometry of the upper and lower control arms, in part, control such parameters as wheel camber, wheel caster and steering angle.
For particular vehicle applications, it may be problematic to package the shock towers, coil springs, struts, connecting rods, and other suspension related hardware. To this end, suspension assemblies have been developed which incorporate a composite spring-like device with a lower suspension member. The lower suspension member supports a portion of the knuckle and is connected to an intermediate spring portion, which provides at least partially, the spring rate for the suspension assembly. However, the composite spring and suspension members of the prior art are rather simple, and are unable to provide the ability to change suspension parameters such as wheel caster. Therefore, what is needed is a suspension assembly having a composite spring and suspension member that provides a change in wheel caster during wheel travel.
The present invention provides a steering assembly for a vehicle including an upper connection, typically provided by an upper control arm. A knuckle includes an upper and lower portions with the upper portion supported by the upper connection. A lower assembly of the present invention includes a control arm with legs extending from a spring portion at spaced apart ends. The legs extend from its ends and converge to a lower connection for supporting the lower portion of the knuckle with the upper and lower connections defining a wheel camber and a wheel caster. Preferably, each of the legs of the control arm has a different spring rate to provide a change in wheel camber under the deflection of the control arm during wheel travel. The different spring rates of the legs permits the lower connection to twist thereby enabling the wheel caster to change slightly during the upward and downward motion of the wheel.
Accordingly, the above invention provides a suspension assembly having a composite spring and suspension member that provides a change in wheel caster during wheel travel.